Flow controllers for powder lacquers

ABSTRACT

A new group of polymer flow controllers for powder resin lacquer is provided. The polymer flow controllers contain groups ##STR1## wherein n and m are numbers from 0 to 1000 with the sum of n+m=2-1000 and R 1  and R 2  are independently hydrogen, an optionally hydroxy substituted hydrocarbon group containing 1 to 36 carbon atoms aryl and aralkyl optionally substituted in the aromatic nucleus, or R 3  --(--O--C 2  H 4  --)-- p  O--CH 2  -- wherein R 3  is an alkyl or alkenyl group containing 1 to 18 carbon atoms and p is a number of 1 to 10.

FIELD OF THE INVENTION

This invention relates to flow controllers for powder lacquerscontaining polymers with oxazoline and/or oxazine monomer units and toprocesses for their production.

BACKGROUND OF THE INVENTION

Low-solvent or solvent-free coating systems are acquiring increasingsignificance. This group of coating systems includes powder coating,i.e. the coating of metals and plastics by application and sintering ofheat-curing powders. They may be applied by rotational coating, powderspraying, fluidized-bed coating and, above all, by electrostaticcoating. Thermoset powder lacquers of epoxy, polyester and acrylicresins are particularly suitable for electrostatic powder coating.Thermoplastics of polyamide, polyester, polyethylene, polyethylene vinylacetate, polyvinyl chloride and polyepoxides are preferably used forfluidized-bed coating. Powder coating is used above all for machineparts and domestic goods (for example steel furniture). To promote theflow of the polymer powder during stoving or sintering, flow controllersare added so that any irregularities formed during application, such asstreaks, bubbles, craters, orange peel structures and pinholes, arelargely eliminated. Known flow controllers include acrylate copolymers.These are generally liquid polyacrylate-based products, for example thecommercial products Perenol® F 40, Perenol® F 30 P mod (Henkel KGaA) orModaflow® (Monsanto), which basically may be incorporated in the powderlacquers by two different methods:

1. A so-called master batch is prepared by melting the liquid flowcontroller into a binder component of the powder lacquer. The solidifiedmelt is then size-reduced and made up for subsequent processing.

2. An inert carrier for the liquid products, for example silica, isused.

The disadvantage of master batch technology is that the formulation ofpowder lacquers is limited because the binder of the master batch has tobe identical or at least compatible with the principal binder of theformulation.

Flow controllers applied to a carrier can lead to a reduction in thegloss of the lacquer and to a reduction in the transparency of clearlacquers and, under adverse conditions, to a deterioration in thestorage stability of the powder lacquer on account of theincompatibility of the generally inorganic carrier with the lacquerfilm.

RELATED ART

In addition, either method gives solid flow controllers containing 100%by weight of active substance. To eliminate these disadvantages,powder-form flow controllers based on polyacrylates have been developed,more particularly for the production of clear lacquers, requiringneither an inert carrier nor a master batch process. One such flowcontroller is described, for example, in EP-A1 0 355 676. Thedisadvantage of these solid polyacrylates is that the improvement inflow obtainable with small quantities is inadequate and, althoughsatisfactory flow properties are obtained where larger quantities areused, the resulting films are cloudy.

In addition, the softening temperatures are still so low that the flowcontrollers can become lumpy after prolonged storage.

Polyoxazolines are known compounds which are obtained in thepolymerization of oxazolines substituted in the 2-position. Theproduction of oxazolines substituted by long-chain alkyl groups isdescribed, for example, in EP-A1 315 858. The cationic polymerization ofoxazolines is comprehensively described, for example, by S. Kobayashiand T. Saegusa in the monograph "Ring Opening Polymerization", Ed. K. J.Ivin, T. Saegusa, Vol. 2, pages 761-790, London, Elsevier, 1984.

5,6-Dihydro4H-1,3-oxazines substituted in the 2-position, hereinafterreferred to as oxazines, are also known compounds of which the synthesisis described, for example, in DE-A1 39 14 155. The polymerization of theoxazines is described in the monograph cited above (pages 791-795).

The copolymerization of oxazolines and oxazines is also known.

Polyoxazolines are produced by living cationic polymerization. It isknown that this polymerization can be carried out in standard reactors,for example glass vessels or stirred tank reactors, in the presence ofsuitable solvents or in the absence of solvents. Where thepolymerization is carried out in the absence of solvents, the fast andhighly exothermic reaction gives rise to the problem of dissipating theheat generated. This is generally done by initially introducing andpolymerizing only part of the monomers and then continuously adding therest in such a way that the heat of reaction can still be dissipated bycooling.

If phenyloxazoline is polymerized in this way, the effect of the highviscosity of the polymer melt at the polymerization temperature is thatthe melt can no longer be stirred in conventional units. Accordingly,the heat of polymerization cannot be dissipated, nor can the polymerformed be further processed.

The problem addressed by the present invention was to provide solid flowcontrollers for powder lacquers based on polymers with oxazoline and/oroxazine monomer units and containing 10 to 100% by weight and preferably100% by weight of active substance which would be easy to incorporate inpowder lacquers, would not lead to lump formation in the powder lacquer,even after prolonged storage, and would form non-cloudy or glossy filmson stoving. More particularly, the problem addressed by the inventionwas to provide a new and more suitable flow controller for powderlacquer systems showing unsatisfactory flow properties with conventionaladditives.

Another problem addressed by the invention was to provide processes forthe production of flow controllers for powder lacquers based on polymerscontaining oxazoline and/or oxazine monomer units with which it would bepossible to dissipate the heat of polymerization without difficulty orto process the highly viscous polymer melts.

BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to flow controllers for powder lacquerscontaining one or more polymers with the following monomer units:##STR2## in which R₁ and R₂ independently of one another representhydrogen and/or an optionally hydroxysubstituted hydrocarbon radicalcontaining 1 to 36 carbon atoms and/or an aryl or aralkyl radicaloptionally substituted in the aromatic nucleus and/or a groupcorresponding to general formula I:

    R.sub.3 --(OC.sub.2 H.sub.5).sub.p --O--CH.sub.2 --        (I)

where

R₃ is an alkyl or alkenyl group containing 1 to 18 carbon atoms, moreespecially a methyl group, and p is a number of 1 to 10,

and the indices n and m independently of one another may assume valuesof 0 to 1000, with the proviso that the sum of n+m is between 2 and1000,

and, if desired, other additives typically encountered in powderlacquers.

The present invention relates to a process for the production of flowcontrollers for powder lacquers containing polymers of the monomer unitsa) and/or b), in which--to produce the polymers--oxazoline and/oroxazine monomers are dissolved in an organic carrier inert to thepolymerization and are subsequently polymerized for 30 minutes to 5hours at temperatures of 80° to 180° C. by addition of a polymerizationinitiator; and to a process for the production of flow controllers forpowder lacquers containing polymers of the monomer units a) and/or b),in which--to produce the polymers--oxazoline and/or oxazine monomers aremixed with the polymerization initiator and the resulting mixture issubsequently introduced into a heated extruder with a temperature rangeof 100° to 300° C., in which the mixture is polymerized and the polymeris extruded.

DETAILED DESCRIPTION OF THE INVENTION

The substituents R₁ and R₂ may be hydrogen or an optionally branchedhydrocarbon radical containing 1 to 36 carbon atoms. The correspondingmonomers are, for example, unsubstituted oxazolines or oxazines ormethyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, n-pentyl,n-hexyl, n-heptyl, 2-ethylpentyl, n-octyl, 2-ethylhexyl, n-nonyl,n-undecyl, n-tridecyl, n-pentadecyl, n-heptadecyl, i-stearyl,n-nonadecyl and n-heneicosanyl, n-tricosane, n-pentacosane,n-heptacosane, n-nonacosane oxazoline or oxazine.

The hydrocarbon radical may be OH-substituted and may represent, forexample, a 5-hydroxypentyl or 11 -hydroxy-8-heptadecenyl radical.

The substituents R₁ and R₂ may also be aromatic or alkyl-substitutedaromatic groups, for example phenyl, naphthyl, 2-methylphenyl,4-methylphenyl, 4-t-butylphenyl or 2-t-butylphenyl groups.

Other substituents in the aromatic nucleus, for example halogen atoms,hydroxyl groups, alkoxyl groups or nitro groups, are also possible.

In addition, the substituents R₁ and R₂ may correspond to generalformula I:

    R.sub.3 --(OC.sub.2 H.sub.4).sub.p --O--CH.sub.2 --        (I)

in which R₃ is an alkyl or alkenyl group containing 1 to 18 carbonatoms, more especially a methyl group, and p is a number of 1 to 10.

The corresponding monomers are derived from ether carboxylic acidscorresponding to formula II:

    R.sub.3 --(OC.sub.2 H.sub.4).sub.p --O--CH.sub.2 --COOH    (II)

which may be obtained, for example, from ethoxylated alcohols byreaction with chloroacetic acid.

The polymers according to the invention are produced from oxazolineand/or oxazine monomers or mixtures of these monomers with the same ordifferent substituents R₁ and R₂ by cationic polymerization.

The polymers may contain between 50 and 100 mole-% of monomer units a)and between 0 and 50 mole-% of monomer units b). Polymers containingonly monomer units a), i.e. polyoxazolines, are preferred.

In one advantageous embodiment of the invention, polymers containingonly oxazoline monomer units, in which the substituent R₁ is a linear orbranched, saturated or monounsaturated hydrocarbon radical containing 7to 36 carbon atoms, more especially a linear, saturated hydrocarbonradical containing 11 to 17 carbon atoms or a phenyl group, arepreferably used. The monomers of such polyoxazolines are derived fromsaturated or monounsaturated fatty acids of natural or synthetic origin(including technical mixtures thereof) with corresponding chain lengthsor from benzoic acid.

Typical representatives of the above-mentioned natural fatty acids arecaprylic, capric, lauric, myristic, palmitic, stearic, arachic,lignoceric and behenic acid and also 12-hydroxystearic and ricinoleicacid. The so-called montanic acids may also be used as startingmaterials for oxazoline monomers.

Homopolymers of monomer units a) may be used in accordance with theinvention, although copolymers in which R₁ represents various groupsaccording to the invention may also be used. A particularly preferredembodiment is characterized by the use of copolymers in which R₁ is asaturated alkyl radical containing 11 to 17 carbon atoms and a phenylgroup.

Both statistical and block copolymers may be used. Statisticalcopolymers obtainable by polymerization of a mixture of the variousmonomers are preferably used. Block copolymers may be obtained in knownmanner by sequential polymerization of various types of monomers.

Physical mixtures of various polyoxazolines may also be used.

The degree of polymerization is the number of monomer units in a polymermolecule. As known to the expert, the degree of polymerization (numberaverage) of the polymer as a whole in a cationic living polymerizationderives directly from the quotient of the number of monomer moleculesand the number of starter molecules. The average (number average) degreeof polymerization of the polymers according to the invention, i.e. thesum total of the indices m+n, is between 2 and 1000, preferably between5 and 25 and more preferably between 5 and 15.

Suitable initiators are any of the compounds known to the expert, forexample methyl tosylate, methyl triflate, boron trifluoride or strongmineral acids, such as toluene sulfonic acid or perchloric acid.However, alkyl halides, for example methyl iodide, may also be used,optionally in combination with salts, such as lithium perchlorate.

Commensurate with the degree of polymerization, the quantities ofinitiator used are between 50 and 0.1 mole-%, based on the molarquantity of monomers.

The polymerization of the oxazolines or oxazines takes place by a livingmechanism, i.e. the polymerization can always be continued by additionof fresh monomers. Accordingly, cationic oxazolinium or oxaziniumterminal groups may be present in the polymers according to theinvention. However, these terminal groups may also be reacted off withnucleophiles, such as water, OH groups or amino groups, to form covalentbonds.

The melting range of the polymers according to the invention is between40° and 200° C. and preferably between 50° and 100° C.

In one process according to the invention for the production of the flowcontrollers containing polymers of monomer units a) and/or b), themonomers are dissolved in an organic carrier inert to the polymerizationand subsequently polymerized. By inert is meant that the polymerizationis not prevented from running its full course. Suitable inert organiccarriers are, for example, fatty alcohols, preferably saturated fattyalcohols, hydrogenated castor oil or other OH-functional compounds.

The quantities of the inert organic carrier are between 10 and 200% byweight and preferably between 50 and 150% by weight, based on theoxazoline or oxazine monomer. After the monomer or monomer mixture hasbeen dissolved in the carrier, the initiator is added and the mixture isheated in a standard reaction vessel until an exothermic reactionbegins. This is generally the case at temperatures of 50° to 150° C.After the exothermic reaction has abated, the reaction mixture is ifnecessary heated to a temperature of 150° to 160° C. and stirred at thattemperature for 3 to 5 hours to complete the polymerization.

According to the invention, the polymers of monomer units a) and/or b)may also be produced using an extruder. This is of particular advantagein the case of particularly viscous polymers based on phenyl oxazolineor copolymers containing phenyl oxazoline. To carry out the process, themonomer or the monomer mixture is mixed with the initiator. The liquidmixture is introduced into the extruder through a metering unit. Thetemperature of the extruder is between 100° and 300° C. It has proved tobe particularly useful to increase the temperature in the extrusionscrew, for example from 100° C. in the feed zone to 150° to 200° C. inthe heating zone and then to 210° to 300° C. in the outlet nozzle. Thepolymerization takes place in the extruder. From the nozzle, the polymeris transported onto a cooling belt. The process enables even highlyviscous polymers, for example polyphenyl oxazoline, to be produced andprocessed.

The polymers of monomer units a) and/or b) may also be produced byinitially introducing part of the monomers with the total quantity ofinitiator into a standard stirred reactor and heating with stirringuntil the polymerization reaction begins. The remaining monomers arethen introduced at temperatures of 120° to 180° C. and preferably attemperatures of 140° to 160° C. at such a rate that the heat ofpolymerization generated can be dissipated by cooling. After theaddition, the reaction mixture is stirred for about 30 minutes at atemperature of around 150° C. to complete the reaction.

The polymers according to the invention are suitable as flow controllersfor powder lacquers.

Powder lacquers are generally produced as follows:

The binder is intensively homogenized in a mixer with pigments, hardenerand additives. Suitable additives are, above all, flow aids, fatty acidesters, such as hydrogenated castor oil, agents for preventingpinholing, such as benzoin, flatting agents, such as polyethylene waxesor silica, hardening accelerators or UV stabilizers. Depending on theapplication, the quantities added may be between 0.1 and 5% by weight,based on the powder lacquer. Although the additives are normally addedas individual substances, it is of course possible to mix the variousadditives to form a single compound known as a flow aid. The quantity ofpolymers containing monomer units a) and/or b) in this compound may bebetween 10 and 100% by weight and is preferably between 20 and 80% byweight, based on the compound.

The mixture of binder, pigments and additives is extruded.

The extrudate is first roughly ground and then finely ground to form apowder lacquer ready for application.

The powder lacquers to be improved in their flow properties by thepolymers according to the invention of monomer units a) and/or b)contain thermoplastic or thermoset synthetic resins and 0.1 to 2.0% byweight and preferably 0.5 to 1% by weight, based on the total weight ofthe powder lacquers, of one or more of the polymers according to theinvention and optionally pigments and typical additives, such ashardeners, hardening accelerators and UV stabilizers. Epoxy-based powderlacquers for crosslinking with carboxyfunctional polyesters (so-calledhybrid systems) and powder lacquers based on carboxyfunctionalpolyesters for crosslinking with triglycidyl isocyanurates arepreferred. In particular, however, it is also possible to produce powderlacquers based on hydroxyfunctional polyacrylates and blockedpolyfunctional isocyanates of the type commercially available as Crelan®VP LS 2995/2007 (Bayer AG). The polymers according to the invention aremore suitable than other flow controllers for these powder lacquers.

The advantages of the new flow controllers lie essentially in theirready processability to powder lacquers, for example during dry blendingand metering, in their relatively high stability in storage, i.e. nolump formation, and in their better flow behavior, for example not onlyare fish eyes, craters and pinholes avoided, the orange-peel effect isalso distinctly reduced.

Above all, the polymers according to the invention provide for theproduction of completely streak-free clear lacquer films and glossypigmented films.

EXAMPLES

All percentages in the Examples are by weight, unless otherwiseindicated.

The products were characterized as follows:

1. The melting range was determined using a Kofler heating bench or byDSC (differential scanning colorimetry).

2. The molecular weight was determined by GPC relative to polystyrenestandards.

3. The OH value was determined in accordance with DIN 53 240.

Example 1

In a 1 liter three-necked flask equipped with a stirrer, internalthermometer, dropping funnel, reflux condenser and nitrogen inlet, 90.8g of nonyl oxazoline (0.46 mole) were mixed with 42.8 g of p-toluenesulfonic acid methyl ester (0.23 mole) and the resulting mixture washeated to 60° C. A highly exothermic reaction began, increasing thetemperature to 120° C. After the exothermic reaction had abated, thereaction mixture was heated to 160° C. and another 363 g of nonyloxazoline (1.84 mole) were added dropwise with stirring at such a ratethat the temperature did not rise above 170° C. After 1 hour, theaddition was terminated. The reaction mixture was then stirred for 1hour at 160° C. The polymer was poured out onto a Teflon film and, aftercooling, was ground to a yellowish powder. It had a molecular weight of2300 (weight average) and a melting range of 59° to 93° C. (DSC).

Example 2

As in Example 1, 103.5 g of undecyl oxazoline were reacted with 42.8 gof p-toluene sulfonic acid methyl ester, after which another 414 g ofundecyl oxazoline were added at 160° C. The polymer was ground to ayellowish powder. It had a molecular weight of 2600 (weight average) anda melting range of 59° to 96° C. (DSC).

Example 3

As in Example 1, 142.4 g of heptadecyl oxazoline were reacted with 42.8g of p-toluene sulfonic acid methyl ester, after which another 570 g ofheptadecyl oxazoline were added at 160° C. The polymer was ground to ayellowish powder. It had a molecular weight of 3900 (weight average) anda melting range of 50° to 94° C. (DSC).

Example 4

In a 1 liter three-necked flask equipped with a stirrer, internalthermometer, dropping funnel, reflux condenser and nitrogen inlet, 356 gof hydrogenated castor oil and 356 g of n-heptadecyl oxazoline weremelted with stirring at 80° C. 21.4 g of p-toluene sulfonic acid methylester were added at that temperature. An exothermic reaction beganimmediately, increasing the temperature to 180° C. After the exothermicreaction had abated, the reaction mixture was cooled to 160° C. andstirred for another 3 hours at that temperature. The product was pouredonto a Teflon film and, after cooling, was ground to a yellowish powder.

Example 5

Production of Polyoxazolines in an Extruder.

A mixture was prepared from 765.6 g of phenyl oxazoline (4.4 moles),217.3 g of n-nonyl oxazoline (1.1 mole) and 10.3 g of p-toluene sulfonicacid methyl ester (0.055 mole). The mixture was introduced through adropping funnel into a Brabender DSK 47/7 extruder at a rate of 10ml/minute. The rotational speed was 20 r.p.m., the torque was 0.8 to1N·m and the pressure was 1 bar.

Temperature profile:

    ______________________________________                                        T1         feed zone:    130° C.                                       T2         second heating zone:                                                                        190° C.                                       T3         third heating zone:                                                                         210° C.                                       T4         slit die:     220° C.                                       ______________________________________                                    

An amber-colored polymer with a viscosity of 17 Pa·s at 200° C., asmeasured with a cone and plate viscosimeter at a shear rate of 625 s⁻¹,was obtained.

Example 6

A mixture was prepared from 1331.5 g of phenyl oxazoline (9.06 moles)and 168.5 g of p-toluene sulfonic acid methyl ester. The mixture wasintroduced through a dropping funnel into a Brabender DSK 47/7 extruderat a rate of 10 ml/minute. The rotational speed was 20 r.p.m., thetorque was 0.8 to 1N·m and the pressure was 1 bar.

Temperature profile:

    ______________________________________                                        T1         feed zone:    130° C.                                       T2         second heating zone:                                                                        190° C.                                       T3         third heating zone:                                                                         210° C.                                       T4         slit die:     220° C.                                       ______________________________________                                    

An amber-colored polymer with a viscosity of 2.6 Pa·s at 200° C., asmeasured with a cone and plate viscosimeter at a shear rate of 625 s⁻¹,and a melting range of 155° to 165° C. was obtained.

Example 7

As in Example 6, a mixture was prepared from 877.8 g of phenyl oxazoline(5.97 moles) and 222.2 g of methyl tosylate (1.19 moles) and introducedinto an extruder.

An amber-colored polymer with a viscosity of 0.4 Pa·s at 200° C., asmeasured with a cone and plate viscosimeter at a shear rate of 625 s⁻¹,and a melting range of 135° to 140° C. was obtained.

Performance Test

To establish their suitability as flow controllers, the copolymers to beused in accordance with the invention were tested in the followingpowder lacquer systems.

A Epoxy Polyester Lacquer (Hybrid System)

A powder lacquer composition of 50 parts by weight of an epoxy resin I,50 parts by weight of a polyester resin II and 0.5 part by weight ofbenzoin was mixed in the presence of 1 part by weight of the flowcontroller to be tested. The mixture was then extruded, granulated,ground and sieved. The powder lacquers obtained were electrostaticallyapplied to a metal surface and stoved for 12 minutes at 180° C. Theepoxy resin used was a commercial product based on bisphenol A andepichlorohydrin. The oil-free polyester resin was also a commercialproduct containing free carboxyl groups. The resins had the followingcharacteristic data:

    ______________________________________                                                           I         II                                               ______________________________________                                        Epoxide equivalent weight                                                                        715-835   --                                               Glass transition temperature °C.                                                          --        43-48                                            Softening range (Kofler) °C.                                                              70-80     70-80                                            Acid value (DIN 53402)                                                                           --        65-80                                            Melt viscosity Pa · s                                                (DIN 53229/160° C./cone plate)                                                            --         8-16                                            (DIN 53735 21.2 N/120° C.)                                                                Approx. 50                                                                              --                                               ______________________________________                                    

The stoving conditions were 5 minutes at 200° C., 8 minutes at 180° C.or 17 minutes at 165° C. (the temperatures shown relate to the objecttemperature).

B Polyester Lacquer

A powder lacquer was prepared as described in A from 93 parts by weightof a polyester resin (III) containing free carboxyl groups and 7 partsby weight of triglycidyl isocyanurate with addition of 1 part by weightof flow controller and was applied to a metal surface. The polyesterresin had the following characteristic data:

    ______________________________________                                                               III                                                    ______________________________________                                        Softening point (Kofler)                                                                             77-87° C.                                       Glass transition temperature                                                                         55-60° C.                                       Melt viscosity DIN 53229, 160° C., cone/plate                                                 30-60 Pa · s                                  Acid value DIN 53402   30-36 mg KOH/g                                         ______________________________________                                    

The stoving conditions were 5 minutes at 200° C., 8 minutes at 180° C.or 17 minutes at 165° C. (the temperatures shown relate to the objecttemperature).

C Acrylate/Blocked Isocyanate (Polyurethane Lacquer)

A powder lacquer was prepared as described in A from 65 parts by weightof a hydroxyfunctional acrylate resin (IV) (Crelan® VP LS 2995, aproduct of Bayer AG) and 35 parts by weight of a blocked isocyanate (V)(Crelan® VP LS 2007, a product of Bayer AG) with addition of 1 part byweight of flow controller and 0.3 part by weight of benzoin and wasapplied to a metal surface.

The resins had the following characteristic data:

    ______________________________________                                                           IV   V                                                     ______________________________________                                        Iodine value DIN 6162                                                         50% in acetone       ≦2                                                                            --                                                60% in tetrahydrofuran                                                                             --     2                                                 Hydroxyl content DIN 53240                                                                         2.4%   --                                                Acid value DIN 53402 15     --                                                NCO content          --     10%                                               ______________________________________                                    

The stoving conditions were 15 minutes at 180° C. or 10 minutes at 200°C. (object temperature).

The flow controllers according to the Examples could be satisfactorilyprocessed and remained free-flowing.

The clear lacquers obtained showed no signs of clouding, even in layerthicknesses of more than 100 μm.

The results of the flow tests are set out in the following Table.

                  TABLE                                                           ______________________________________                                        Lacquer system                                                                           Additive    Evaluation                                                                             Clouding                                      ______________________________________                                        A          --          5        No                                            Polyester/ Ex. 1       3        No                                            Epoxy      Ex. 3       1        No                                                       Ex. 7       4        No                                                       F 30 p      1-2      Yes                                                      mod                                                                B          --          5        No                                            Polyester/ Ex. 1       3        No                                            TGIC       Ex. 2       3        No                                                       Ex. 3       1        No                                                       F 30 p      1        Yes                                                      mod                                                                C          --          5        No                                            Polyacrylate/                                                                            Ex. 2       1        No                                            Isocyanate Ex. 3       0-1      No                                                       F 30 p       2-31    Yes                                                      mod                                                                ______________________________________                                         TGIC is trisglycidyl isocyanurate                                             F 30 p mod is a solid flow controller based on a polyacrylate applied to      SiO.sub.2 (Perenol F 30 p mod, Henkel KGaA).                                  Evaluation of Flow:                                                           0 Excellent flow, substantially flat film surface                             1 Good flow, slight texture                                                   2 Moderate flow, orangepeel effect                                            3 As 2, occasional pinholes, slight depressions                               4 Moderate flow, occasional craters, numerous pinholes                        5 Poor flow, numerous craters                                            

Flow results in the 1 to 2 category are typical of powder lacquers andare accepted in industry.

We claim:
 1. In a method wherein an additive is incorporated in a powderlacquer formation to control the flow properties of the powder lacquerduring coating formation, the improvement which comprises: incorporatingin the power lacquer formulation a composition containing at least oneflow controller polymer containing at least one group selected from thegroup consisting of ##STR3## wherein R₁ and R₂ are independentlyhydrogen, an optionally hydroxysubstituted hydrocarbon group containing1 to 36 carbon atoms, an aryl group, an aralkyl group optionallysubstituted on the aromatic nucleus, and a group of the formulaR₃--(--OC₂ H₄ --)--_(p) O--CH₂ -- where R₃ is alkyl or alkenyl containing1 to 18 carbon atoms, p is a number of 1 to 10, n and m, independently,are from 0 to 1000 with the sum of n and m being from 2 to 1000, andoptionally containing additives typically encountered in powder lacquerformulations.
 2. The method claimed in claim 1, wherein the polymercontains50 to 100 mole-% of groups a) and 0 to 50 mole-% of groups b),based on the total molar quantity of groups a)+b).
 3. The method claimedin claim 1, wherein the substituents R¹ and R² are independentlyselected from the croup consisting of linear hydrocarbon groupscontaining 11 to 17 carbon atoms and phenyl groups.
 4. The methodclaimed in claim 1, wherein the sum of the indices n+m is between 5 and25.
 5. The method claimed in claim 1, wherein the composition is amixture containing10 to 100% by weight of at least one flow controllerpolymer containing at least one group selected from The group consistingof group a) and b) and 0 to 90% by weight of additives, based on theweight of The flow controller polymer.
 6. A process for the productionof flow controllers for powder lacquers, said flow controller containingpolymers comprising at least one group selected from the groupconsisting of groups a) and b) of claim 1, which comprises: mixing atleast one of oxazoline and oxazine monomers which form polymerscontaining at least one of a) or b), with a polymerization initiator toform a mixture and introducing the mixture into an extruder operated ata temperature in a range of 100° to 300° C., wherein the mixture ispolymerized and the polymer is extruded.
 7. The method of claim 1,wherein the polymer contains 100 mole % of the group ##STR4##
 8. Themethod of claim 7, wherein for each group, R₁ is independently selectedfrom linear hydrocarbon groups containing 11 to 17 carbon atoms and nhas a value of 5 to
 15. 9. The method of claim 3, wherein the sum of nand m is from 5 to
 25. 10. The method claimed in claim 2, wherein thesubstituents R¹ and R² are independently selected from the groupconsisting of linear hydrocarbon groups containing 11 to 17 carbon atomsand phenyl groups.
 11. The method claimed in claim 2, wherein the sum ofn and m is from 6 to
 25. 12. The method claimed in claim 2, wherein thecomposition is a mixture containing10 to 100% by weight of at least oneflow controller polymer containing at least one group selected from thegroup consisting of group a) and b) and 0 to 90% by weight of additives,based on the weight of the flow controller polymer.
 13. The method ofclaim 2, wherein the polymer contains 100 mole % of the group ##STR5##14. The method of claim 13, wherein for each group, R₁ is independentlyselected from linear hydrocarbon groups containing 11 to 17 carbon atomsand n has a value of 5 to
 15. 15. The method claimed in claim 3, whereinthe composition is a mixture containing10 to 100% by weight of at leastone flow controller polymer containing at least one group selected fromthe group consisting of group a) and b) and 0 to 90% by weight ofadditives, based on the weight of the flow controller polymer.
 16. Themethod of claim 3, wherein the polymer contains 100 mole % of the group##STR6##
 17. The method of claim 16, wherein for each group, R₁ isindependently selected from linear hydrocarbon groups containing 11 to17 carbon atoms and n has a value of 5 to
 15. 18. The method of claim 5,wherein the polymer contains 100 mole % of the group ##STR7##
 19. Themethod of claim 18, wherein for each group, R₁ is independently selectedfrom linear hydrocarbon groups containing 11 to 17 carbon atoms and nhas a value of 5 to 15.